BlackTreeIndependent security intelligence

Full vulnerability report · 2026

CVE-2026-65612High confidence

Shell Command Injection in nnn

nnn · nnn

5.1MediumCVSS 4.0

Recommended action

Scheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Fix not verified

Distribution package intelligence

Ubuntu vendor package status

Canonical’s release and source-package findings are shown separately from local repository availability.

1 package state

Repository candidate not checked

A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.

Ubuntu release	Source package	Vendor state	Fixed version	Evidence
Ubuntu 24.04 LTSnoble · standard archive	`nnn`	Under evaluationCanonical reports that the package might be affected and still needs evaluation or fixing.	`Not published in this feed`	Canonical record ↗Source updated 9 Sept 2026

Direct vendor intelligence

Authoritative vendor CSAF and VEX advisories

Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.

1 current

CVE-2026-65612 · CSAF 2.0 · revision 3 · finalRed Hat Product Securitynnn: nnn: Arbitrary code execution via crafted filename

1 known not affected

The vendor explicitly states that these products are not affected by this CVE.

All currently supported Red Hat products

Summary: A flaw was found in nnn. An attacker can exploit this vulnerability by placing a file with a specially crafted name, containing shell syntax, on a shared filesystem, removable media, or within an extracted archive. If a victim then navigates to and opens this file using the `preview-tabbed` feature, the malicious filename is embedded into a generated shell command. This allows the attacker's injected payload to execute with the privileges of the nnn process, leading to arbitrary code execution.
Remediation: No remediation text is recorded.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current

ENISA EUVD identifier

EUVD-2026-62401

No EUVD known-exploited evidence

nnn does not sanitize the filename variable. An attacker can place a file with a crafted name on a shared filesystem, removable media, or inside an extracted archive whose name contains a single quote followed by shell syntax. If the victim navigates to that file and opens it with preview-tabbed, the filename is embedded into the generated shell command and the injected payload executes with the privileges of the nnn process. Maintainer of this project was notified about this vulnerability. It might has been addressed, but the maintainer did not provide a vulnerable version range. Only version 5.2 was tested and confirmed as vulnerable.

EUVD state: Present in the current official mapping
Known exploitation: Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score: 5.1 · CVSS 4.0
Advisory evidence: No linked advisory details stored yet

Recommended actionScheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Fix not verified

What, why and how

What

Why

Untrusted input is incorporated into an operating-system command without safe parameter handling.

How

An attacker operating through a network path may attempt exploitation when the stated preconditions are met. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

Why

Untrusted input is incorporated into an operating-system command without safe parameter handling.

How

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation

Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.

No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material

Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.

None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path: a network path → Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface: Network
Privileges required: None: unauthenticated exploitation is possible
User interaction: Active interaction required
Attack complexity: Low: no specialised conditions are recorded
Security boundary: Not a CVSS 4.0 base metric
Weakness ? CWE means Common Weakness Enumeration: a standard category for the underlying weakness.: CWE-78 ↗
CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection'). The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component.
CVSS vector ? CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:L/VA:N/SC:L/SI:L/SA:L
Common Vulnerability Scoring System 4.0: the compact vector below is decoded into plain language.
AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.ATNoneAttack requirements: No additional deployment or execution condition is required.PRNonePrivileges required: The attacker does not need an account or existing privileges.UIActiveUser interaction: A user must take a deliberate action for exploitation to succeed.VCNoneVulnerable-system confidentiality: No direct loss is represented by this metric.VILowVulnerable-system integrity: A successful attack can cause a limited loss.VANoneVulnerable-system availability: No direct loss is represented by this metric.SCLowSubsequent-system confidentiality: A successful attack can cause a limited loss.SILowSubsequent-system integrity: A successful attack can cause a limited loss.SALowSubsequent-system availability: A successful attack can cause a limited loss.
Post-exploitation / living off the land: No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.

NetworkUnauthenticatedCWE-78

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2026-62401Official EUVD mapping

Official EUVD record

CERT Polska · Polish · CVE-2026-65609CERT Polska w social mediach

CERT Polska otrzymał zgłoszenie o podatnościach w oprogramowaniu nnn i koordynował proces ujawniania informacji. Podatność CVE-2026-65609 : nnn jest podatny na atak typu Out-of-Bounds Write. Oprogramowanie nie sprawdza długości danych wczytywanych z pliku sesji za pomocą opcji -s . Atakujący, który umieści złośliwy plik sesji w katalogu ofiary, może wykorzystać ten błąd do zapisu danych poza buforem i uszkodzenia stanu aplikacji. Podatność CVE-2026-65610 : nnn przechowuje zmienną homelen jako typ uchar_t , który może reprezentować wyłącznie wartości z zakresu 0-255. Atakujący, który jest w stanie wpływać na środowisko wykonawcze ofiary, może dostarczyć dowolną ścieżkę HOME, której długość określona jako 0. Wyrażenie (homelen - 1) zostaje następnie rozpoznane jako typ signed int , przyjmując wartość -1, co prowadzi do odczytu oraz zapisu poza granicami bufora, jeden bajt przed buforem przechowującym ścieżkę. Podatność CVE-2026-65611 : nnn nie przeprowadza poprawnie sanityzacji zmiennej ścieżki. Atakujący może utworzyć katalog ze złośliwą nazwą w udostępnionym systemie plików, na nośniku wymiennym lub w archiwum. Gdy ofiara wejdzie do tego katalogu w nnn i użyje funkcji wsadowego kopiowania lub przenoszenia plików, złośliwa nazwa zostanie osadzona w poleceniu powłoki. W rezultacie atakujący może wykonać swój kod z uprawnieniami procesu nnn. Podatność CVE-2026-65612 : nnn nie przeprowadza odpowiedniej sanityzacji nazw plików. Atakujący może umieścić plik o specjalnie spreparowanej nazwie w udostępnionym systemie plików, na nośniku wymiennym lub wewnątrz rozpakowanego archiwum, którego nazwa zawiera pojedynczy apostrof, po którym następuje składnia powłoki systemowej. Jeżeli ofiara przejdzie do takiego pliku i otworzy go za pomocą funkcji preview-tabbed , nazwa pliku zostanie osadzona w generowanym poleceniu powłoki. W rezultacie wstrzyknięty ładunek zostanie wykonany z uprawnieniami procesu nnn. Twórca projektu został powiadomiony o tych podatnościach. Możliwe, że zostały one zaadresowane, jednak twórca nie podał zakresu podatnych wersji. Tylko wersja 5.2 została przetestowana i potwierdzona jako podatna.

Official advisory

Patch and workaround

Operational remediation based on structured source evidence.

Status ? Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.: Fix not verified
Affected: 5.2
Fixed: No fixed version is explicitly recorded in the structured CVE data.
Action: No verified patch reference is present in the current structured sources. Check the vendor advisory before making a change.
Workaround: No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.

Evidence and provenance

Published 19 Aug 2026 · Last source change 20 Aug 2026, 15:57 UTC · CWE-78 · Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

CVE recordCVE.org · 5.2

CVSS sourceCNA

EPSS source

The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.

FIRST · tracked since 2026-08-23

European sourceENISA EUVD · EUVD-2026-62401

Product sourceCNA

Remediation sourceCVE/CNA references

CWE sourceCNA

NVD statusNVD not scheduled

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates →

19 Aug 2026, 13:21 UTC
Catalogue recordCVE added to the BlackTree catalogue.
CNA ↗

2026-08-19CVE published

ENISA EUVD · EUVD-2026-62401↗Vendor CSAF · Red Hat Product Security↗CVE authority or vendor reference↗Official CVE record (CNA and ADP data)↗NVD record↗

Technical terms and abbreviations used in this report

CVE: Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS: Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS: Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE: Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA: CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP: Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD: National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT: A computer security incident response team that publishes warnings or coordinates incident response.
PoC: Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF: Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL: Living off the land: abuse of legitimate tools or system functions during an attack.